1. Technical Field
The present invention relates to an apparatus and method for transporting automobiles by converting a semi-trailer from carrying general freight cargo to carrying automobiles. More specifically, the present invention provides for a lift mechanism which is powered by the drive wheels of the automobile being carried by the lift so that a plurality of automobiles may be carried in two levels in an enclosed semi-trailer. Alternative embodiments of the method of the present invention provide for transportation of automobiles by semi-trailers alone, by piggy-back transportation on railcars or by intermodal shipping containers. As used herein, the terms "semi-trailer" or "enclosed semi-trailer" should be understood to include standard intermodal shipping containers also.
2. Description of the Prior Art
The transportation of automobiles from the manufacturer to the dealer is normally by means of specialized automobile hauling trailers, trucks and railcars. Trailers and trucks designed for carrying automobiles are uniquely adapted for high efficiency in carriage of that particular type of commodity and are not suitable for use as general freight carriers. General freight, by contrast, is normally carried in enclosed semi-trailers which can carry a wide variety of-goods since they do not possess the unique specialized adaptations required for carrying automobiles.
The two types of vehicles described above, namely the automobile carrying trailer and the general freight carrying trailer, are thus adapted to their own particular mode of operation and are unable to carry the type of freight for which the other is adapted. However, while the less specialized general freight carrying semi-trailer is able to haul a wide variety of goods, excepting automobiles, the automobile carrying trailer is so highly specialized that it is unable to haul any other type of freight other than the automobiles for Which it is uniquely adapted. Thus, while general freight carrying trailers are normally able to arrange for transportation of goods on both legs of a round trip, the automobile carrying trailer is normally left to return empty from a particular designation.
The consequence of this situation is that automobile carrying trailers and trucks are often under-utilized which translates into high per-mile cost and generally higher freight rates.
Another disadvantage to the use of the specialized types of automobile carrying trailers is that they are generally open to the elements which exposes their cargo to vandalism and damage from environmental factors.
To solve the problems identified above, the present invention provides for an apparatus and method for converting an enclosed semi-trailer from the carriage of general freight to the carriage of automobiles. This concept of converting semi-trailers for carrying both general freight and automobiles is not new. For example, U.S. Pat. No. 5,051,046 issued to Oren on Sep. 24, 1991 for "Semi-Trailer Convertible for Hauling Automobiles" discloses an enclosed semi-trailer having tracks for the support of an upper level of automobiles. Likewise, U.S. Pat. No. 4,786,222 issued to Blodgett on Nov. 22, 1988 for "Folding Automobile Storage Deck Assembly" discloses a semi-trailer equipped to be used for either automobile or general freight transportation in which swiveling deck sections are provided for carrying two layers of automobiles. Also the same concept has been applied to the transportation of automobiles in standard intermodal shipping containers; e.g., U.S. Pat. No. 4,911,590 issued to Green on Mar. 27, 1990 for "Automobile Loading Rack and Method for Loading into Containers." Other patents which disclose the general concept of converting an enclosed trailer to the carriage of automobiles include U.S. Pat. Nos. 2,668,734 and 2,636,772. Also of interest are U.S. Pat. Nos. 4,701,086, 2,659,318 and 2,432,228.
Each of these patents generally disclose some means for carrying automobiles in a two-level configuration through the use of ramps or elevators.
In each of the patents cited above, the elevator or ramp mechanism is powered by an external source, for example, hydraulic rams or electric motors. The present invention provides for a lift mechanism which is operated by the drive wheels of the automobile being lifted into the upper position. Various concepts for employing the drive wheels of a vehicle to power a lift or elevator have been disclosed in the prior art. Examples of such concepts are disclosed in U.S. Pat. Nos. 3,637,099, 3,521,728, 2,754,933, 2,579,688, 2,538,517, 2,497,472 and 1,751,874. Such concepts have even been disclosed for use in connection with toy vehicles; e.g., U.S. Pat. No. 4,582,500. To the best knowledge of the inventor, however, the concept of an automobile powered lift has never been applied to the unique problems in converting an enclosed semi-trailer from the carriage of general freight to the carriage of automobiles.
It is important to note that many of the same problems identified above in relation to specialized trailers and trucks for the carriage of automobiles also are true of the specialized railcars required for the transportation of automobiles by rail. The apparatus and method of the present invention is also adaptable to being employed in the rail transportation of automobiles through the use of the "piggyback" system for the transportation of enclosed semi-trailers. By preloading automobiles into semi-trailers using the method and apparatus of the present invention, greater flexibility and efficiency in the rail transportation of automobiles is possible. In addition, the method and apparatus of the present invention may also be applied to loading and transportation of automobiles in standard intermodal shipping containers. Loading automobiles into shipping containers has all the advantages of shipping semi-trailers "piggyback" by rail and in addition shipping containers may be double stacked for even greater efficiencies. Throughout the following discussion of the present invention, the preferred embodiments, and claims, the use of the terms "semi-trailer" or "enclosed semi-trailer" are intended to embrace intermodal shipping containers also except where specifically distinguished.